Since the creation of the flexible walled tube, their have been some that have had a need to squeeze the last possible drop of material from each tube. To assist with this goal, in 1928 E. L. Rostier received U.S. Pat. No. 1,770,946, which disclosed a key for collapsible folding tubes. Then in 1950, A. A. F. Kruger was issued U.S. Pat. No. 2,531,060 for an adapter for collapsible tube winding. Kruger's adapter included a housing into which an associated winding key (fitted to the end of a flexible tube) could be inserted and easily rotated. In 2001, Liberatore received U.S. Pat. No. 6,247,618 for a roll-up tube dispenser with shell housing. In Liberatore, the adapter like housing had a clam-shell design that allowed a key to be easily inserted into the housing.